JP2006-009923A, published by the Japan Patent Office in 2006, proposes a tensioner which exerts a tensile force on an endless belt. The tensioner comprises an arm supporting a tension pulley on a tip, a base member which supports the arm to rotate about the base member, and a torsion coil spring exerting a rotational force on the arm with respect to the base member.
The endless belt is looped around the tension pulley. According to the rotational force acting on the arm, the tension pulley pushes the endless belt inward or outward so as to generate a predetermined tensile force on the endless belt.
A bolt penetrating a bolt hole formed in the central portion of the base member is screwed into a fixed member so as to fix the base member to the fixed member.